Family-run · South East London · Since 2019
Ductwork, MVHR, extract systems and air conditioning — designed, installed and commissioned across Beckenham, Bromley, West Wickham, Chislehurst, Dulwich and South East London.
Most people arrive here with a symptom rather than a diagnosis, and the symptom is usually enough to narrow it down. Each of these explains what is happening and what genuinely fixes it — no form, no email address, just the answer.
Water running down the glass from October to March, and pooling on the sill. What it means, when it is ordinary and when it is not — and why the glass is the only surface in the room honest enough to show you.
Read the explanationYou cleaned it, you sprayed it, you painted over it, and six weeks later it returned in the same shape. Why that shape is the diagnosis, why anti-mould paint runs out, and how to tell which of the three damps you have.
Read the explanationA fan running is not a fan working. The eight things that go wrong — starting with the one you can check yourself today with a torch and a loft hatch, which is the worst of them and the most common.
Read the explanationNew windows, insulation, a loft conversion, a new kitchen. Not a coincidence and usually not a botched job — every trade did their own work correctly, and nobody was responsible for the air.
Read the explanationDomestic and commercial ventilation, heating and cooling — designed properly, installed neatly, and commissioned so the airflow is measured rather than assumed.
Whole-house mechanical ventilation with heat recovery — designed, ducted and balanced so every room gets its share without throwing your heating out of the window.
Rigid and spiral ductwork, sized and routed to keep resistance and noise down. Set out square and bracketed properly — because on an exposed run the setting-out is the finish.
Air handling units and fan coil units set, connected and commissioned — plinths, anti-vibration mounts, flexible connections and access left where the next person can actually reach it.
Bathroom, kitchen and utility extract that meets the Part F rate at the grille, not just on the box. Ducted to outside properly, never into a loft void.
One unit in the loft — or on the wall of a flat with no loft — pushing filtered air gently into the whole house. The least disruptive whole-house answer to condensation.
Installation and planned maintenance for split and multi-split systems — filters, coils, condensate and performance checked before the hot weather finds the fault for you.
A system nobody services stops doing what it was installed to do, quietly. A booked visit every year, every valve measured, and the figure written next to last year’s — from £199 a year.
Measurement first: humidity, surface temperatures and actual extract rates. You get a written report on what is causing it, not a guess and a quote for a bigger fan.
Supply and extract for units, venues and workspaces — coordinated with the other trades so the ductwork lands where the ceiling design says it should.
Investigation, a written report naming the cause, the fix, and a dated evidence trail — because under the Homes (Fitness for Human Habitation) Act the question is not only whether you fixed it, but whether you can show what you did and when.
Heat recovery, in section
An extract fan throws your heating out through the wall. A heat recovery unit takes the warmth out of the stale air on its way past and hands it to the fresh air coming in. Scroll to follow one lungful of air all the way through the machine.
Illustrative figures for a good counterflow unit — about 90% heat recovery — on a 3 °C day. Manufacturers quote up to roughly 90% for this type; the real numbers depend on the unit and the duct layout, and are proved by measurement at commissioning, not by the brochure. The efficiency also depends on the filters being changed: a loaded set drops the airflow and takes the recovery down with it.
Extract · 21 °C
A valve in the bathroom ceiling pulls air out continuously — from the rooms where the moisture is actually made. It leaves at room temperature, taking the moisture with it before it reaches a cold wall and turns into condensation.
Exhaust · 5 °C
Through a filter, through one half of the exchanger, through the fan and out to the wall grille. By the time it reaches the outside it is close to outdoor temperature — the warmth you paid for has been left behind in the unit.
Intake · 3 °C
Filtered outdoor air enters through its own grille, set well away from the exhaust so the unit can't breathe back in what it has just thrown out, and runs into the other half of the exchanger. The plates keep the two streams apart: heat passes between them, air never does.
Supply · 19 °C
The warmed fresh air is delivered to the bedrooms and living room. That is the whole trick: the full air change the regulations ask for, without paying to heat the house twice — which is exactly what an extract fan on its own makes you do.
About us
Cavalli Ventilation is a family-run business in South East London. Niki has worked in ventilation since 2003 and has traded as Cavalli Ventilation since July 2019. His father works alongside him, and his son joins them when they are busy. The person who comes out and looks at your property is the person who does the work.
We are ventilation engineers first. We design, install and commission MVHR, MEV, PIV, extract systems, air handling units, ductwork, duct socks and air conditioning, across both commercial and residential work. That is the reason our damp surveys measure the ventilation rather than just recommending you improve it — it is the system we install for a living, and we can prove what it achieves before and after.
We do not do bodge jobs. Every install is left as though it were going in our own home — set out properly, finished properly, commissioned to a measured rate and documented. If it does not look right, it is not finished.
You deal with the same engineers from survey to commissioning. No call centre, no subcontracted crew you have never met, and no job signed off without the airflow measured. And you follow the whole job in our own client app — quotes, documents, servicing dates and a direct line to your engineer.
Both held by this business — the certificates are published on the site.
Every install is signed off with a calibrated anemometer at the grille. A fan rated at 30 l/s routinely delivers far less once ducting, bends and a terminal are on it — the only number that counts is the one measured in your room.
In their words. Every one of these is a real review you can check.
Had work done by us? Leave a review on Google — it takes a minute and it is how other people in your street find us.
Send us a message with what you have noticed at home. We will tell you honestly whether you need a survey, a system, or neither.
Or see what it costs — unlike most in this trade, we publish our prices.
Trained on the systems we install
Most trade sites show you a row of logos. These are the actual certificates, held by this business. Tap either one to read it, or download the PDF.
